ML20062D047

/01t-0 on 781025:during LPPT in Mode 2,containment Air Lock Was Opened to Repair Failed Oper Mechanism & Was Kept Ajar,Due to Misunderstanding Between Supervisor & Maintenance Personnel.All Personnel Have Been Reinstructed

ML20062D047
Person / Time
Site:	Calvert Cliffs
Issue date:	11/13/1978
From:	Carroll J, Romney K BALTIMORE GAS & ELECTRIC CO.
To:
Shared Package
ML20062D045	List: ML20062D043 ML20062D047
References
LER-78-038-01T, LER-78-38-1T, NUDOCS 7811170187
Download: ML20062D047 (2)

Text

NRC F ORM 366 U.S. NUCLEAR REGULATORY COMMISSION 87-77)

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1. 60 66 DOCE E T NOUu(R 68 69 EVENT DATk 14 75 REPORT DATE 80 EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h O 2 l During LPPT. with the reactor in rrde 2. the Contairment mir inck inner 1 0 a i door was opened at 1600 on 10/27/78 to repair a failed operating meen- 1 0 4 l anism. Contrary to the reouirements of T.S.3.6.1.3 the inner door I O s l remained open until 0930 on 10/31/78 at which time repairs were completed I O s I and air lock again became operable. Contrary to recuirements of T.S. I O i l 3.0.h the reactor was made critical at 2000 on 10/28/78 following a 1 0 s l trip at 1905 on 10/27/78. The outer air lock door remained shut and I k $'OE "#"o*E CO seCEE COMPONENT CODE SUB DE SU E O 9 8

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44 CAUSE DESCRIPTION AND CORREC flVE ACTIONS 27 iO l This event was caused by a broken cam follower, McGill Mfg. Co. part # l l CF-1-S. The broken follower was replaced and the operation of the inner I i 7 l door checked. The interlock was then tested for proper operation and I d _ ,1 l the door returned to service. The broken cam follower is being invest- l i 4 l igated by maintenance and metallurgical personnel to determine i 7 W 9 80

$1 $  % POWE R OTHERSTATUS O SCO R DISCOVERY DESCRIPTION i s

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CONTINUATICN SHEET! #03:

LER 78-38/1T IDCKET NO. 50-318 EVENT DATE 10/25/78 PEPORT DATE 11/13/78 EVENT DESCRIPTION AND PROBABLE CCNSEQUENCES: (Continued) locked throughout this event. Since each air lock door is designed to with-stand post IDCA conditions, it may be concluded that neither the health nor

/I safety of the public was jeopardized by this event. With a single door

- shut, sealed and locked, the level of containment integrity provided by the personnel air lock is comparable to that provided by the equipment access hatch which is also a single barrier.

.. CAUSE DESCRIPTION: (Continued)

(' ' approy.riate steps to prevent recurrence.

Failure to maintain both doors closed while effecting repairs resulted f

from a misunderstanding between the Shift Supervisor and the maintenance personnel repairing the operating mechanism. The Shift Supervisor was informed that the interlock had been defeated pending completion of repairs and the.t the outer door had been padlocked. He assumed that the inner door 'was also shut. However, maintenance personnel, unaware that

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the T.S. requited both doors to be shut, left the inner door ajar. To prevent recurrence of this event, operations personnel have been counseled regarding'the circumstances surrounding this event and its potential consequences, s

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